1. Technical Field
The present disclosure generally relates to friction stir welding, and particularly, to a friction stir welding method using a joining tool without a mixing pin.
2. Description of Related Art
Friction stir welding is widely used to join aluminum alloy because it is simple to perform.
A metal structure of the stirred product can be constituently uneven, since the material of the stirred portion of the product plastically flows in the friction stir welding process. After treatment, the different areas, specifically the stirred and unstirred portions of the product, may exhibit different aspects, wherein the joining portion of the workpieces provides an unfavorable appearance. Despite product annealing, the difference of the joined portion persists. Therefore, this can not satisfy a product with the stirred surface presented as an outer surface.
Achievement of a favorable appearance in products obtained by friction stir welding remains a challenge.
Therefore, an improved friction stir welding method is desired to overcome the described limitations.